"The earthquake hit at 5:18 p.m. local time, roughly 180 miles off Japan's Pacific coast. Two aftershocks, 6.2- and 5.5-magnitude quakes, followed within 30 minutes.

"And Japan, an island nation stretching across some of the world's most seismically active fault lines, experienced a rerun of post-quake trauma, with trains halting, cell phone networks tying up, and with broadcasters on NHK urging coastal residents to flee for their lives.

"Waves between 3 feet and several inches hit the coasts, with no major signs of damage, based on initial media reports. But thousands had to evacuate their homes — mostly in the fishing towns whose low-lying areas were flattened 21 months ago."

The BBC reports that with Japan's early warning system, NHK was able to broadcast warnings just before the earthquake struck.

The BBC spoke to John Heritage, an English teacher in Miyagi Prefecture.

"The students were kind of worried. Normally they're pretty calm, but they looked concerned. Then the tsunami alarm started going off and we evacuated to higher ground," he told the BBC.

Luckily, there have been no reprots of serious damage. We'll update this post if that changes.